This invention relates to improvements in self-priming centrifugal pumps reducing wear in such pumps and providing them with an extended operating life as well as a capability of pumping, without perceptible damage, liquids entraining a great variety of particulate solid materials, such as sand, pebbles, small stones, gravel and the like. A pump embodying the features of the present invention has been found capable of handling solids as large as one-half the pipe size of the pump. It is therefore particularly advantageous for use as a trash handling pump and will be so described, but only by way of example and not by way of limitation.
While the prior art has produced numerous trash handling pumps they have presented serious maintenance problems in their use. They are normally plagued with early and severe damage to their impeller and volute structures due to the nature and character of the materials which they pump. In many cases their design is such, moreover, that their seals depend for lubrication on the dirty liquid which is passed through the pump. Under such circumstances it has been found that the pump seals tend to quickly deteriorate. In these respects the design of prior art trash handling pumps has been something less than satisfactory.
It is to the solution of the aforementioned problems as well as the provision of a simplified construction for a centrifugal pump that the present invention is directed.
For art of pertinence to the present invention, attention is directed to U.S. Pat. No. 3,543,368.